8f8 Scientific Intelligence — Geology. 



injurious is the process of denuding the slopes of the Alps of 

 their woody covering, a process which unfortunately is every 

 day, and every where, rapidly accomplishing ; since the neces- 

 sary consequence is, that thus the disintegration rapidly proceeds, 

 and the way is opened up whereby avalanches, and immense 

 blocks of rocks, descend to the lowest and most cultivated parts 

 of the valleys. — Escher in Bib. Universel. 



16. On the Chalk and Calcaire grossier ofMeudon. — M. Des- 

 hayes has lately communicated to the Philomathic Society of 

 Paris, some observations which he made in a quarry at Bos 

 Meudon, in which may be seen, as stated by M. d'Archiac to 

 the Geological Society of France, the immediate contact of chalk 

 and of the calcaire grossier, both of the formations, according 

 to M. Deshayes, being clearly distinguished by the fossils they 

 contain, — fossils which are altogether different in the two for- 

 mations (terrains). In this quarry is to be found, immediately 

 above the hard chalk, or caillasse, a bed of calcaire grossier, then 

 different alternating strata of limestone, marl, and plastic clay ; 

 then the thick bed of plastic clay, and finally the upper calcaire 

 grossier. The fissures, also, which penetrate into the chalk, 

 proceeding from the upper surface of the bed of caillasse, are 

 filled with a limestone which contains the shells of the calcaire 

 grossier, which appears to M. Deshayes to confirm his opinion 

 concerning the fixed distinction betwixt the two formations 

 (terrains) which are superposed upon each other. M. Deshayes 

 then, from these circumstances, maintains, that it ought not to 

 be admitted as a general proposition, that the oldest tertiary for- 

 mation is the lacustrine or plastic clay formation ; he thinks 

 that the distinction between the chalk and the tertiary forma- 

 tion, a distinction which is accurately determined by the differ- 

 ence of the fossils peculiar to these two geological epochs, leads 

 us to recognise at Meudon, tertiary marine strata, analogous to 

 the calcaire grossier, and yet situated underneath the plastic 

 clay, and in immediate contact with the chalk. M. Elie de 

 Beaumont, who has also examined the same quarry, stated to 

 the Society that his observations had led him to quite a different 

 conclusion. He thinks that the separation between the chalk 

 formation and the tertiary strata is especially determined by the 

 marked traces of distinct erosion which the waters have every 



